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<tr class="t-nv"><td colspan="5"> <a href="span.html" title="cpp/header/span"><tt>&lt;span&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="array.html" title="cpp/header/array"><tt>&lt;array&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="vector.html" title="cpp/header/vector"><tt>&lt;vector&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="deque.html" title="cpp/header/deque"><tt>&lt;deque&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="forward_list.html" title="cpp/header/forward list"><tt>&lt;forward_list&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="list.html" title="cpp/header/list"><tt>&lt;list&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="map.html" title="cpp/header/map"><tt>&lt;map&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="set.html" title="cpp/header/set"><tt>&lt;set&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="queue.html" title="cpp/header/queue"><tt>&lt;queue&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="unordered_map.html" title="cpp/header/unordered map"><tt>&lt;unordered_map&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="unordered_set.html" title="cpp/header/unordered set"><tt>&lt;unordered_set&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="stack.html" title="cpp/header/stack"><tt>&lt;stack&gt;</tt></a></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Iterators</td></tr>
<tr class="t-nv"><td colspan="5"> <strong class="selflink"><tt>&lt;iterator&gt;</tt></strong></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Ranges</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ranges.html" title="cpp/header/ranges"><tt>&lt;ranges&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Algorithms</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="algorithm.html" title="cpp/header/algorithm"><tt>&lt;algorithm&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="execution.html" title="cpp/header/execution"><tt>&lt;execution&gt;</tt></a> <span class="t-mark-rev t-since-cxx17">(C++17)</span></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Numerics</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="complex.html" title="cpp/header/complex"><tt>&lt;complex&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="random.html" title="cpp/header/random"><tt>&lt;random&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="valarray.html" title="cpp/header/valarray"><tt>&lt;valarray&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="numeric.html" title="cpp/header/numeric"><tt>&lt;numeric&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="bit.html" title="cpp/header/bit"><tt>&lt;bit&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="numbers.html" title="cpp/header/numbers"><tt>&lt;numbers&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cfenv.html" title="cpp/header/cfenv"><tt>&lt;cfenv&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cmath.html" title="cpp/header/cmath"><tt>&lt;cmath&gt;</tt></a></td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Input/Output</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="iosfwd.html" title="cpp/header/iosfwd"><tt>&lt;iosfwd&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ios.html" title="cpp/header/ios"><tt>&lt;ios&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="iomanip.html" title="cpp/header/iomanip"><tt>&lt;iomanip&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="streambuf.html" title="cpp/header/streambuf"><tt>&lt;streambuf&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="istream.html" title="cpp/header/istream"><tt>&lt;istream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ostream.html" title="cpp/header/ostream"><tt>&lt;ostream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="iostream.html" title="cpp/header/iostream"><tt>&lt;iostream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="syncstream.html" title="cpp/header/syncstream"><tt>&lt;syncstream&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="spanstream.html" title="cpp/header/spanstream"><tt>&lt;spanstream&gt;</tt></a> <span class="t-mark-rev t-since-cxx23">(C++23)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="sstream.html" title="cpp/header/sstream"><tt>&lt;sstream&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="fstream.html" title="cpp/header/fstream"><tt>&lt;fstream&gt;</tt></a></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cstdio.html" title="cpp/header/cstdio"><tt>&lt;cstdio&gt;</tt></a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cinttypes.html" title="cpp/header/cinttypes"><tt>&lt;cinttypes&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="strstream.html" title="cpp/header/strstream"><tt>&lt;strstream&gt;</tt></a> <span class="t-mark">(C++98/)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Regular expressions</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="regex.html" title="cpp/header/regex"><tt>&lt;regex&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Filesystem support</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="filesystem.html" title="cpp/header/filesystem"><tt>&lt;filesystem&gt;</tt></a> <span class="t-mark-rev t-since-cxx17">(C++17)</span></td></tr>
<tr class="t-nv-h2"><td colspan="5"> Thread support</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="thread.html" title="cpp/header/thread"><tt>&lt;thread&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="atomic.html" title="cpp/header/atomic"><tt>&lt;atomic&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="mutex.html" title="cpp/header/mutex"><tt>&lt;mutex&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="shared_mutex.html" title="cpp/header/shared mutex"><tt>&lt;shared_mutex&gt;</tt></a> <span class="t-mark-rev t-since-cxx14">(C++14)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="condition_variable.html" title="cpp/header/condition variable"><tt>&lt;condition_variable&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span>  </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="future.html" title="cpp/header/future"><tt>&lt;future&gt;</tt></a> <span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="stop_token.html" title="cpp/header/stop token"><tt>&lt;stop_token&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="semaphore.html" title="cpp/header/semaphore"><tt>&lt;semaphore&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="latch.html" title="cpp/header/latch"><tt>&lt;latch&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="barrier.html" title="cpp/header/barrier"><tt>&lt;barrier&gt;</tt></a> <span class="t-mark-rev t-since-cxx20">(C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <br>
</td></tr>
</table></div></td></tr>
<tr class="t-nv-h2"><td colspan="5"> C compatibility</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="cstdbool.html" title="cpp/header/cstdbool"><tt>&lt;cstdbool&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ccomplex.html" title="cpp/header/ccomplex"><tt>&lt;ccomplex&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="ctgmath.html" title="cpp/header/ctgmath"><tt>&lt;ctgmath&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="cstdalign.html" title="cpp/header/cstdalign"><tt>&lt;cstdalign&gt;</tt></a> <span class="t-mark">(C++11/17/20)</span></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="ciso646.html" title="cpp/header/ciso646"><tt>&lt;ciso646&gt;</tt></a> <span class="t-mark-rev t-until-cxx20">(until C++20)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="stdatomic.h.html" title="cpp/header/stdatomic.h"><tt>&lt;stdatomic.h&gt;</tt></a></td></tr>
</table></div></td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div></div>
<p>This header is part of the <a href="../iterator.html" title="cpp/iterator">iterator</a> library.
</p>
<table class="t-dsc-begin">

<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Concepts">Concepts</span></h3>
</td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Iterator_concepts">  Iterator concepts </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"> <span class="t-lines"><span>indirectly_readable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies that a type is indirectly readable by applying operator <code>*</code>  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_writable.html" title="cpp/iterator/indirectly writable"> <span class="t-lines"><span>indirectly_writable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a value can be written to an iterator's referenced object <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/weakly_incrementable.html" title="cpp/iterator/weakly incrementable"> <span class="t-lines"><span>weakly_incrementable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a <a href="../concepts/semiregular.html" title="cpp/concepts/semiregular"><code>semiregular</code></a> type can be incremented with pre- and post-increment operators  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/incrementable.html" title="cpp/iterator/incrementable"> <span class="t-lines"><span>incrementable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that the increment operation on a <a href="../iterator/weakly_incrementable.html" title="cpp/iterator/weakly incrementable"><code>weakly_incrementable</code></a> type is equality-preserving and that the type is <a href="../concepts/equality_comparable.html" title="cpp/concepts/equality comparable"><code>equality_comparable</code></a>  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/input_or_output_iterator.html" title="cpp/iterator/input or output iterator"> <span class="t-lines"><span>input_or_output_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that objects of a type can be incremented and dereferenced  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/sentinel_for.html" title="cpp/iterator/sentinel for"> <span class="t-lines"><span>sentinel_for</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies a type is a sentinel for an <a href="../iterator/input_or_output_iterator.html" title="cpp/iterator/input or output iterator"><code>input_or_output_iterator</code></a> type  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/sized_sentinel_for.html" title="cpp/iterator/sized sentinel for"> <span class="t-lines"><span>sized_sentinel_for</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that the <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">-</span></span></span> operator can be applied to an iterator and a sentinel to calculate their difference in constant time  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/input_iterator.html" title="cpp/iterator/input iterator"> <span class="t-lines"><span>input_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a type is an input iterator, that is, its referenced values can be read and it can be both pre- and post-incremented  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/output_iterator.html" title="cpp/iterator/output iterator"> <span class="t-lines"><span>output_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a type is an output iterator for a given value type, that is, values of that type can be written to it and it can be both pre- and post-incremented   <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/forward_iterator.html" title="cpp/iterator/forward iterator"> <span class="t-lines"><span>forward_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that an <a href="../iterator/input_iterator.html" title="cpp/iterator/input iterator"><code>input_iterator</code></a> is a forward iterator, supporting equality comparison and multi-pass  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/bidirectional_iterator.html" title="cpp/iterator/bidirectional iterator"> <span class="t-lines"><span>bidirectional_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a <a href="../iterator/forward_iterator.html" title="cpp/iterator/forward iterator"><code>forward_iterator</code></a> is a bidirectional iterator, supporting movement backwards  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/random_access_iterator.html" title="cpp/iterator/random access iterator"> <span class="t-lines"><span>random_access_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a <a href="../iterator/bidirectional_iterator.html" title="cpp/iterator/bidirectional iterator"><code>bidirectional_iterator</code></a> is a random-access iterator, supporting advancement in constant time and subscripting  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/contiguous_iterator.html" title="cpp/iterator/contiguous iterator"> <span class="t-lines"><span>contiguous_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a <a href="../iterator/random_access_iterator.html" title="cpp/iterator/random access iterator"><code>random_access_iterator</code></a> is a contiguous iterator, referring to elements that are contiguous in memory  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Indirect_callable_concepts">  Indirect callable concepts </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_unary_invocable.html" title="cpp/iterator/indirectly unary invocable"> <span class="t-lines"><span>indirectly_unary_invocable</span><span>indirectly_regular_unary_invocable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies that a callable type can be invoked with the result of dereferencing an <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> type <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirect_unary_predicate.html" title="cpp/iterator/indirect unary predicate"> <span class="t-lines"><span>indirect_unary_predicate</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies that a callable type, when invoked with the result of dereferencing an <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> type, satisfies <a href="../concepts/predicate.html" title="cpp/concepts/predicate"><code>predicate</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirect_binary_predicate.html" title="cpp/iterator/indirect binary predicate"> <span class="t-lines"><span>indirect_binary_predicate</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a callable type, when invoked with the result of dereferencing two <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> types, satisfies <a href="../concepts/predicate.html" title="cpp/concepts/predicate"><code>predicate</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirect_equivalence_relation.html" title="cpp/iterator/indirect equivalence relation"> <span class="t-lines"><span>indirect_equivalence_relation</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that a callable type, when invoked with the result of dereferencing two <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> types, satisfies <a href="../concepts/equivalence_relation.html" title="cpp/concepts/equivalence relation"><code>equivalence_relation</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirect_strict_weak_order.html" title="cpp/iterator/indirect strict weak order"> <span class="t-lines"><span>indirect_strict_weak_order</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies that a callable type, when invoked with the result of dereferencing two <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> types, satisfies <a href="../concepts/strict_weak_order.html" title="cpp/concepts/strict weak order"><code>strict_weak_order</code></a> <br> <span class="t-mark">(concept)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Common_algorithm_requirements">  Common algorithm requirements </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_movable.html" title="cpp/iterator/indirectly movable"> <span class="t-lines"><span>indirectly_movable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that values may be moved from an <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> type to an <a href="../iterator/indirectly_writable.html" title="cpp/iterator/indirectly writable"><code>indirectly_writable</code></a> type  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_movable_storable.html" title="cpp/iterator/indirectly movable storable"> <span class="t-lines"><span>indirectly_movable_storable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies that values may be moved from an <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> type to an <a href="../iterator/indirectly_writable.html" title="cpp/iterator/indirectly writable"><code>indirectly_writable</code></a> type and that the move may be performed via an intermediate object  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_copyable.html" title="cpp/iterator/indirectly copyable"> <span class="t-lines"><span>indirectly_copyable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  specifies that values may be copied from an <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> type to an <a href="../iterator/indirectly_writable.html" title="cpp/iterator/indirectly writable"><code>indirectly_writable</code></a> type  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_copyable_storable.html" title="cpp/iterator/indirectly copyable storable"> <span class="t-lines"><span>indirectly_copyable_storable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that values may be copied from an <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> type to an <a href="../iterator/indirectly_writable.html" title="cpp/iterator/indirectly writable"><code>indirectly_writable</code></a> type and that the copy may be performed via an intermediate object <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_swappable.html" title="cpp/iterator/indirectly swappable"> <span class="t-lines"><span>indirectly_swappable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that the values referenced by two <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> types can be swapped <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_comparable.html" title="cpp/iterator/indirectly comparable"> <span class="t-lines"><span>indirectly_comparable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies that the values referenced by two <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> types can be compared <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/permutable.html" title="cpp/iterator/permutable"> <span class="t-lines"><span>permutable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies the common requirements of algorithms that reorder elements in place  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/mergeable.html" title="cpp/iterator/mergeable"> <span class="t-lines"><span>mergeable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies the requirements of algorithms that merge sorted sequences into an output sequence by copying elements  <br> <span class="t-mark">(concept)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/sortable.html" title="cpp/iterator/sortable"> <span class="t-lines"><span>sortable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   specifies the common requirements of algorithms that permute sequences into ordered sequences  <br> <span class="t-mark">(concept)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Classes">Classes</span></h3>
</td></tr>


<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Algorithm_utilities"> Algorithm utilities </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirect_result_t.html" title="cpp/iterator/indirect result t"> <span class="t-lines"><span>indirect_result_t</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  computes the result of invoking a callable object on the result of dereferencing some set of <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> types <br> <span class="t-mark">(alias template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/projected.html" title="cpp/iterator/projected"> <span class="t-lines"><span>projected</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   helper template for specifying the constraints on algorithms that accept projections <br> <span class="t-mark">(class template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Associated_types"> Associated types </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/incrementable_traits.html" title="cpp/iterator/incrementable traits"> <span class="t-lines"><span>incrementable_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   computes the difference type of a <a href="../iterator/weakly_incrementable.html" title="cpp/iterator/weakly incrementable"><code>weakly_incrementable</code></a> type  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/indirectly_readable_traits.html" title="cpp/iterator/indirectly readable traits"> <span class="t-lines"><span>indirectly_readable_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   computes the value type of an <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a> type  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/iter_t.html" title="cpp/iterator/iter t"> <span class="t-lines"><span>iter_value_t</span><span>iter_reference_t</span><span>iter_const_reference_t</span><span>iter_difference_t</span><span>iter_rvalue_reference_t</span><span>iter_common_reference_t</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   computes the associated types of an iterator  <br> <span class="t-mark">(alias template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Primitives"> Primitives </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/iterator_traits.html" title="cpp/iterator/iterator traits"> <span class="t-lines"><span>iterator_traits</span></span></a></div></div>
</td>
<td>   provides uniform interface to the properties of an iterator <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/iterator_tags.html" title="cpp/iterator/iterator tags"> <span class="t-lines"><span>input_iterator_tag</span><span>output_iterator_tag</span><span>forward_iterator_tag</span><span>bidirectional_iterator_tag</span><span>random_access_iterator_tag</span><span>contiguous_iterator_tag</span></span></a></div><div><span class="t-lines"><span></span><span></span><span></span><span></span><span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   empty class types used to indicate iterator categories <br> <span class="t-mark">(class)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/iterator.html" title="cpp/iterator/iterator"> <span class="t-lines"><span>iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark">(deprecated in C++17)</span></span></span></div></div>
</td>
<td>   base class to ease the definition of required types for simple iterators  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Adaptors"> Adaptors </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/reverse_iterator.html" title="cpp/iterator/reverse iterator"> <span class="t-lines"><span>reverse_iterator</span></span></a></div></div>
</td>
<td>   iterator adaptor for reverse-order traversal <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/move_iterator.html" title="cpp/iterator/move iterator"> <span class="t-lines"><span>move_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   iterator adaptor which dereferences to an rvalue reference  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/move_sentinel.html" title="cpp/iterator/move sentinel"> <span class="t-lines"><span>move_sentinel</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   sentinel adaptor for use with <span class="t-lc"><a href="../iterator/move_iterator.html" title="cpp/iterator/move iterator">std::move_iterator</a></span>  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/common_iterator.html" title="cpp/iterator/common iterator"> <span class="t-lines"><span>common_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   adapts an iterator type and its sentinel into a common iterator type  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/default_sentinel.html" title="cpp/iterator/default sentinel t"> <span class="t-lines"><span>default_sentinel_t</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   default sentinel for use with iterators that know the bound of their range  <br> <span class="t-mark">(class)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/counted_iterator.html" title="cpp/iterator/counted iterator"> <span class="t-lines"><span>counted_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   iterator adaptor that tracks the distance to the end of the range  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/unreachable_sentinel_t.html" title="cpp/iterator/unreachable sentinel t"> <span class="t-lines"><span>unreachable_sentinel_t</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   sentinel that always compares unequal to any <a href="../iterator/weakly_incrementable.html" title="cpp/iterator/weakly incrementable"><code>weakly_incrementable</code></a> type  <br> <span class="t-mark">(class)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/back_insert_iterator.html" title="cpp/iterator/back insert iterator"> <span class="t-lines"><span>back_insert_iterator</span></span></a></div></div>
</td>
<td>   iterator adaptor for insertion at the end of a container  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/front_insert_iterator.html" title="cpp/iterator/front insert iterator"> <span class="t-lines"><span>front_insert_iterator</span></span></a></div></div>
</td>
<td>   iterator adaptor for insertion at the front of a container  <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/insert_iterator.html" title="cpp/iterator/insert iterator"> <span class="t-lines"><span>insert_iterator</span></span></a></div></div>
</td>
<td>   iterator adaptor for insertion into a container <br> <span class="t-mark">(class template)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Stream_Iterators"> Stream Iterators </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/istream_iterator.html" title="cpp/iterator/istream iterator"> <span class="t-lines"><span>istream_iterator</span></span></a></div></div>
</td>
<td>   input iterator that reads from <span class="t-lc"><a href="../io/basic_istream.html" title="cpp/io/basic istream">std::basic_istream</a></span> <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ostream_iterator.html" title="cpp/iterator/ostream iterator"> <span class="t-lines"><span>ostream_iterator</span></span></a></div></div>
</td>
<td>   output iterator that writes to <span class="t-lc"><a href="../io/basic_ostream.html" title="cpp/io/basic ostream">std::basic_ostream</a></span> <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/istreambuf_iterator.html" title="cpp/iterator/istreambuf iterator"> <span class="t-lines"><span>istreambuf_iterator</span></span></a></div></div>
</td>
<td>   input iterator that reads from <span class="t-lc"><a href="../io/basic_streambuf.html" title="cpp/io/basic streambuf">std::basic_streambuf</a></span> <br> <span class="t-mark">(class template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ostreambuf_iterator.html" title="cpp/iterator/ostreambuf iterator"> <span class="t-lines"><span>ostreambuf_iterator</span></span></a></div></div>
</td>
<td>   output iterator that writes to <span class="t-lc"><a href="../io/basic_streambuf.html" title="cpp/io/basic streambuf">std::basic_streambuf</a></span> <br> <span class="t-mark">(class template)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Customization_point_objects">Customization point objects</span></h3>
</td></tr>

<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in  namespace <code>std::ranges</code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ranges/iter_move.html" title="cpp/iterator/ranges/iter move"> <span class="t-lines"><span>iter_move</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   casts the result of dereferencing an object to its associated rvalue reference type <br> <span class="t-mark">(customization point object)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ranges/iter_swap.html" title="cpp/iterator/ranges/iter swap"> <span class="t-lines"><span>iter_swap</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   swaps the values referenced by two dereferenceable objects  <br> <span class="t-mark">(customization point object)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Constants"> Constants</span></h3>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/unreachable_sentinel_t.html" title="cpp/iterator/unreachable sentinel t"> <span class="t-lines"><span>unreachable_sentinel</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   an object of type <code>unreachable_sentinel_t</code> that always compares unequal to any <a href="../iterator/weakly_incrementable.html" title="cpp/iterator/weakly incrementable"><code>weakly_incrementable</code></a> type  <br> <span class="t-mark">(constant)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/default_sentinel.html" title="cpp/iterator/default sentinel t"> <span class="t-lines"><span>default_sentinel</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   an object of type <code>default_sentinel_t</code> used with iterators that know the bound of their range  <br> <span class="t-mark">(constant)</span> </td></tr>


<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Functions">Functions</span></h3>
</td></tr>


<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Adaptors_2"> Adaptors </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/make_reverse_iterator.html" title="cpp/iterator/make reverse iterator"> <span class="t-lines"><span>make_reverse_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx14">(C++14)</span></span></span></div></div>
</td>
<td>   creates a <span class="t-lc"><a href="../iterator/reverse_iterator.html" title="cpp/iterator/reverse iterator">std::reverse_iterator</a></span> of type inferred from the argument <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/make_move_iterator.html" title="cpp/iterator/make move iterator"> <span class="t-lines"><span>make_move_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   creates a <span class="t-lc"><a href="../iterator/move_iterator.html" title="cpp/iterator/move iterator">std::move_iterator</a></span> of type inferred from the argument <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/front_inserter.html" title="cpp/iterator/front inserter"> <span class="t-lines"><span>front_inserter</span></span></a></div></div>
</td>
<td>   creates a <span class="t-lc"><a href="../iterator/front_insert_iterator.html" title="cpp/iterator/front insert iterator">std::front_insert_iterator</a></span> of type inferred from the argument <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/back_inserter.html" title="cpp/iterator/back inserter"> <span class="t-lines"><span>back_inserter</span></span></a></div></div>
</td>
<td>   creates a <span class="t-lc"><a href="../iterator/back_insert_iterator.html" title="cpp/iterator/back insert iterator">std::back_insert_iterator</a></span> of type inferred from the argument <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/inserter.html" title="cpp/iterator/inserter"> <span class="t-lines"><span>inserter</span></span></a></div></div>
</td>
<td>   creates a <span class="t-lc"><a href="../iterator/insert_iterator.html" title="cpp/iterator/insert iterator">std::insert_iterator</a></span> of type inferred from the argument <br> <span class="t-mark">(function template)</span> </td></tr>


<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Non-member_operators"> Non-member operators </span></h5>
</td></tr>


<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/move_iterator/operator_cmp.html" title="cpp/iterator/move iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span><span>operator&lt;=&gt;</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx11">(C++11)</span><span class="t-mark-rev t-until-cxx20">(removed in C++20)</span></span><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  compares the underlying iterators  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/move_iterator/operator%2B.html" title="cpp/iterator/move iterator/operator+"> <span class="t-lines"><span>operator+</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   advances the iterator <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/move_iterator/operator-.html" title="cpp/iterator/move iterator/operator-"> <span class="t-lines"><span>operator-</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   computes the distance between two iterator adaptors <br> <span class="t-mark">(function template)</span> </td></tr>


<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/reverse_iterator/operator_cmp.html" title="cpp/iterator/reverse iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator&lt;</span><span>operator&lt;=</span><span>operator&gt;</span><span>operator&gt;=</span><span>operator&lt;=&gt;</span></span></a></div><div><span class="t-lines"><span></span><span></span><span></span><span></span><span></span><span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  compares the underlying iterators  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/reverse_iterator/operator%2B.html" title="cpp/iterator/reverse iterator/operator+"> <span class="t-lines"><span>operator+</span></span></a></div></div>
</td>
<td>   advances the iterator <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/reverse_iterator/operator-.html" title="cpp/iterator/reverse iterator/operator-"> <span class="t-lines"><span>operator-</span></span></a></div></div>
</td>
<td>   computes the distance between two iterator adaptors <br> <span class="t-mark">(function template)</span> </td></tr>


<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/counted_iterator/operator_cmp.html" title="cpp/iterator/counted iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator&lt;=&gt;</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>  compares the distances to the end  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/counted_iterator/operator%2B.html" title="cpp/iterator/counted iterator/operator+"> <span class="t-lines"><span>operator+</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   advances the iterator <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/counted_iterator/operator-.html" title="cpp/iterator/counted iterator/operator-"> <span class="t-lines"><span>operator-</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   computes the distance between two iterator adaptors <br> <span class="t-mark">(function template)</span> </td></tr>


<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/istream_iterator/operator_cmp.html" title="cpp/iterator/istream iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div><div><span class="t-lines"><span></span><span><span class="t-mark-rev t-until-cxx20">(removed in C++20)</span></span></span></div></div>
</td>
<td>   compares two <code>istream_iterator</code>s  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/istreambuf_iterator/operator_cmp.html" title="cpp/iterator/istreambuf iterator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div><div><span class="t-lines"><span></span><span><span class="t-mark-rev t-until-cxx20">(removed in C++20)</span></span></span></div></div>
</td>
<td>   compares two <code>istreambuf_iterator</code>s  <br> <span class="t-mark">(function template)</span> </td></tr>


<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Operations"> Operations </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/advance.html" title="cpp/iterator/advance"> <span class="t-lines"><span>advance</span></span></a></div></div>
</td>
<td>   advances an iterator by given distance  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/distance.html" title="cpp/iterator/distance"> <span class="t-lines"><span>distance</span></span></a></div></div>
</td>
<td>   returns the distance between two iterators  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/next.html" title="cpp/iterator/next"> <span class="t-lines"><span>next</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   increment an iterator  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/prev.html" title="cpp/iterator/prev"> <span class="t-lines"><span>prev</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   decrement an iterator  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ranges/advance.html" title="cpp/iterator/ranges/advance"> <span class="t-lines"><span>ranges::advance</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   advances an iterator by given distance or to a given bound  <br> <span class="t-mark">(niebloid)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ranges/distance.html" title="cpp/iterator/ranges/distance"> <span class="t-lines"><span>ranges::distance</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   returns the distance between an iterator and a sentinel, or between the beginning and end of a range  <br> <span class="t-mark">(niebloid)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ranges/next.html" title="cpp/iterator/ranges/next"> <span class="t-lines"><span>ranges::next</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   	increment an iterator by a given distance or to a bound  <br> <span class="t-mark">(niebloid)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/ranges/prev.html" title="cpp/iterator/ranges/prev"> <span class="t-lines"><span>ranges::prev</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   decrement an iterator by a given distance or to a bound  <br> <span class="t-mark">(niebloid)</span> </td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Range_access"> Range access </span></h5>
</td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/begin.html" title="cpp/iterator/begin"> <span class="t-lines"><span>begin</span><span>cbegin</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx14">(C++14)</span></span></span></div></div>
</td>
<td>   returns an iterator to the beginning of a container or array <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/end.html" title="cpp/iterator/end"> <span class="t-lines"><span>end</span><span>cend</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span><span><span class="t-mark-rev t-since-cxx14">(C++14)</span></span></span></div></div>
</td>
<td>   returns an iterator to the end of a container or array  <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/rbegin.html" title="cpp/iterator/rbegin"> <span class="t-lines"><span>rbegin</span><span>crbegin</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx14">(C++14)</span></span></span></div></div>
</td>
<td>   returns a reverse iterator to the beginning of a container or array <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/rend.html" title="cpp/iterator/rend"> <span class="t-lines"><span>rend</span><span>crend</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx14">(C++14)</span></span></span></div></div>
</td>
<td>   returns a reverse end iterator for a container or array <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/size.html" title="cpp/iterator/size"> <span class="t-lines"><span>size</span><span>ssize</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div>
</td>
<td>   returns the size of a container or array <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/empty.html" title="cpp/iterator/empty"> <span class="t-lines"><span>empty</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div>
</td>
<td>   checks whether the container is empty <br> <span class="t-mark">(function template)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="../iterator/data.html" title="cpp/iterator/data"> <span class="t-lines"><span>data</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div>
</td>
<td>   obtains the pointer to the underlying array <br> <span class="t-mark">(function template)</span> </td></tr>
</table>
<h3><span class="mw-headline" id="Synopsis">Synopsis</span></h3>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;compare&gt;</span>
<span class="co2">#include &lt;concepts&gt;</span>
 
<span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw1">using</span> <span class="coMULTI">/*with-reference*/</span> <span class="sy1">=</span> T<span class="sy3">&amp;</span><span class="sy4">;</span>  <span class="co1">// exposition only</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> concept <span class="coMULTI">/*can-reference*/</span>       <span class="co1">// exposition only</span>
    <span class="sy1">=</span> requires <span class="br0">{</span> <span class="kw1">typename</span> <span class="coMULTI">/*with-reference*/</span><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> concept <span class="coMULTI">/*dereferenceable*/</span>     <span class="co1">// exposition only</span>
    <span class="sy1">=</span> requires<span class="br0">(</span>T<span class="sy3">&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
      <span class="br0">{</span> <span class="sy2">*</span>t <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> <span class="coMULTI">/*can-reference*/</span><span class="sy4">;</span>  <span class="co1">// not required to be equality-preserving</span>
    <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="co1">// associated types</span>
  <span class="co1">// incrementable traits</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> incrementable_traits<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">using</span> iter_difference_t <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// indirectly readable traits</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> indirectly_readable_traits<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">using</span> iter_value_t <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// iterator traits</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span> <span class="kw1">struct</span> iterator_traits<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="kw1">struct</span> iterator_traits<span class="sy1">&lt;</span>T<span class="sy2">*</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="coMULTI">/*dereferenceable*/</span> T<span class="sy1">&gt;</span>
    <span class="kw1">using</span> iter_reference_t <span class="sy1">=</span> decltype<span class="br0">(</span><span class="sy2">*</span>declval<span class="sy1">&lt;</span>T<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">namespace</span> ranges <span class="br0">{</span>
    <span class="co1">// customization point objects</span>
    <span class="kw1">inline</span> <span class="kw1">namespace</span> <span class="coMULTI">/* unspecified */</span> <span class="br0">{</span>
      <span class="co1">// ranges​::​iter_move</span>
      <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> iter_move <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
 
      <span class="co1">// ranges​::​iter_swap</span>
      <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> iter_swap <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="br0">}</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="coMULTI">/*dereferenceable*/</span> T<span class="sy1">&gt;</span>
    requires requires<span class="br0">(</span>T<span class="sy3">&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
      <span class="br0">{</span> <a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>t<span class="br0">)</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> <span class="coMULTI">/*can-reference*/</span><span class="sy4">;</span>
    <span class="br0">}</span>
  <span class="kw1">using</span> iter_rvalue_reference_t
    <span class="sy1">=</span> decltype<span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>declval<span class="sy1">&lt;</span>T<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="co1">// iterator concepts</span>
  <span class="co1">// concept indirectly_readable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In<span class="sy1">&gt;</span>
    concept indirectly_readable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>indirectly_readable T<span class="sy1">&gt;</span>
    <span class="kw1">using</span> iter_common_reference_t <span class="sy1">=</span>
      common_reference_t<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>, iter_value_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="co1">// concept indirectly_writable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Out, <span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept indirectly_writable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept weakly_incrementable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept weakly_incrementable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept incrementable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept incrementable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept input_or_output_iterator</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept input_or_output_iterator <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept sentinel_for</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> S, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept sentinel_for <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept sized_sentinel_for</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> S, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> disable_sized_sentinel_for <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> S, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept sized_sentinel_for <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept input_iterator</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept input_iterator <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept output_iterator</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept output_iterator <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept forward_iterator</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept forward_iterator <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept bidirectional_iterator</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept bidirectional_iterator <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept random_access_iterator</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept random_access_iterator <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept contiguous_iterator</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept contiguous_iterator <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// indirect callable requirements</span>
  <span class="co1">// indirect callables</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept indirectly_unary_invocable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept indirectly_regular_unary_invocable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept indirect_unary_predicate <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I1, <span class="kw1">class</span> I2<span class="sy1">&gt;</span>
    concept indirect_binary_predicate <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I1, <span class="kw1">class</span> I2 <span class="sy1">=</span> I1<span class="sy1">&gt;</span>
    concept indirect_equivalence_relation <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I1, <span class="kw1">class</span> I2 <span class="sy1">=</span> I1<span class="sy1">&gt;</span>
    concept indirect_strict_weak_order <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span>... <span class="me1">Is</span><span class="sy1">&gt;</span>
    requires <span class="br0">(</span>indirectly_readable<span class="sy1">&lt;</span>Is<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> ...<span class="br0">)</span> <span class="sy3">&amp;&amp;</span> invocable<span class="sy1">&lt;</span>F, iter_reference_t<span class="sy1">&lt;</span>Is<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span>
      <span class="kw1">using</span> indirect_result_t <span class="sy1">=</span> invoke_result_t<span class="sy1">&lt;</span>F, iter_reference_t<span class="sy1">&lt;</span>Is<span class="sy1">&gt;</span>...<span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="co1">// projected</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>indirectly_readable I, indirectly_regular_unary_invocable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> Proj<span class="sy1">&gt;</span>
    <span class="kw1">struct</span> <a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>weakly_incrementable I, <span class="kw1">class</span> Proj<span class="sy1">&gt;</span>
    <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span><a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy1">&lt;</span>I, Proj<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="co1">// common algorithm requirements</span>
  <span class="co1">// concept indirectly_movable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_movable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_movable_storable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept indirectly_copyable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_copyable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_copyable_storable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept indirectly_swappable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I1, <span class="kw1">class</span> I2 <span class="sy1">=</span> I1<span class="sy1">&gt;</span>
    concept indirectly_swappable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept indirectly_comparable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I1, <span class="kw1">class</span> I2, <span class="kw1">class</span> R, <span class="kw1">class</span> P1 <span class="sy1">=</span> identity, <span class="kw1">class</span> P2 <span class="sy1">=</span> identity<span class="sy1">&gt;</span>
    concept indirectly_comparable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept permutable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept permutable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept mergeable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I1, <span class="kw1">class</span> I2, <span class="kw1">class</span> Out,
      <span class="kw1">class</span> R <span class="sy1">=</span> <a href="../functional/ranges/less.html"><span class="kw2847">ranges::<span class="me2">less</span></span></a>, <span class="kw1">class</span> P1 <span class="sy1">=</span> identity, <span class="kw1">class</span> P2 <span class="sy1">=</span> identity<span class="sy1">&gt;</span>
    concept mergeable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// concept sortable</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> R <span class="sy1">=</span> <a href="../functional/ranges/less.html"><span class="kw2847">ranges::<span class="me2">less</span></span></a>, <span class="kw1">class</span> P <span class="sy1">=</span> identity<span class="sy1">&gt;</span>
    concept sortable <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="co1">// primitives</span>
  <span class="co1">// iterator tags</span>
  <span class="kw1">struct</span> input_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> output_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> forward_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> input_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> bidirectional_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> forward_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> random_access_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> bidirectional_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> contiguous_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> random_access_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="co1">// iterator operations</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> InputIt, <span class="kw1">class</span> Distance<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">void</span> advance<span class="br0">(</span>InputIt<span class="sy3">&amp;</span> i, Distance n<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> InputIt<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw1">typename</span> iterator_traits<span class="sy1">&lt;</span>InputIt<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">difference_type</span>
      distance<span class="br0">(</span>InputIt first, InputIt last<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> InputIt<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> InputIt
      next<span class="br0">(</span>InputIt x, <span class="kw1">typename</span> iterator_traits<span class="sy1">&lt;</span>InputIt<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">difference_type</span> n <span class="sy1">=</span> <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> BidirIt<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> BidirIt
      prev<span class="br0">(</span>BidirIt x, ypename iterator_traits<span class="sy1">&lt;</span>BidirIt<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">difference_type</span> n <span class="sy1">=</span> <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="co1">// range iterator operations</span>
  <span class="kw1">namespace</span> ranges <span class="br0">{</span>
    <span class="co1">// ranges​::​advance</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> <span class="kw4">void</span> advance<span class="br0">(</span>I<span class="sy3">&amp;</span> i, iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> <span class="kw4">void</span> advance<span class="br0">(</span>I<span class="sy3">&amp;</span> i, S bound<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> advance<span class="br0">(</span>I<span class="sy3">&amp;</span> i, iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n, S bound<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// ranges​::​distance</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> distance<span class="br0">(</span>I first, S last<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>range R<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> range_difference_t<span class="sy1">&lt;</span>R<span class="sy1">&gt;</span> distance<span class="br0">(</span>R<span class="sy3">&amp;&amp;</span> r<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// ranges​::​next</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> I next<span class="br0">(</span>I x<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> I next<span class="br0">(</span>I x, iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> I next<span class="br0">(</span>I x, S bound<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> I next<span class="br0">(</span>I x, iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n, S bound<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// ranges​::​prev</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>bidirectional_iterator I<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> I prev<span class="br0">(</span>I x<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>bidirectional_iterator I<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> I prev<span class="br0">(</span>I x, iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>bidirectional_iterator I<span class="sy1">&gt;</span>
      <span class="kw4">constexpr</span> I prev<span class="br0">(</span>I x, iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n, I bound<span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span>
 
  <span class="co1">// predefined iterators and sentinels</span>
  <span class="co1">// reverse iterators</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It<span class="sy1">&gt;</span> <span class="kw1">class</span> reverse_iterator<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                              <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy3">!</span><span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                              <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                             <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                             <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                              <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                              <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, three_way_comparable_with<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> compare_three_way_result_t<span class="sy1">&lt;</span>It1, It2<span class="sy1">&gt;</span>
      operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                             <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
      <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>y.<span class="me1">base</span><span class="br0">(</span><span class="br0">)</span> <span class="sy2">-</span> x.<span class="me1">base</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span> operator<span class="sy2">+</span><span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span> n,
                                             <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span> make_reverse_iterator<span class="br0">(</span>It i<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
      requires <span class="br0">(</span><span class="sy3">!</span>sized_sentinel_for<span class="sy1">&lt;</span>It1, It2<span class="sy1">&gt;</span><span class="br0">)</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> disable_sized_sentinel_for<span class="sy1">&lt;</span>reverse_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span>,
                                                     reverse_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;&gt;</span> <span class="sy1">=</span> <span class="kw2">true</span><span class="sy4">;</span>
 
  <span class="co1">// insert iterators</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span> <span class="kw1">class</span> back_insert_iterator<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> back_insert_iterator<span class="sy1">&lt;</span>Container<span class="sy1">&gt;</span> back_inserter<span class="br0">(</span>Container<span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span> <span class="kw1">class</span> front_insert_iterator<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> front_insert_iterator<span class="sy1">&lt;</span>Container<span class="sy1">&gt;</span> front_inserter<span class="br0">(</span>Container<span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span> <span class="kw1">class</span> insert_iterator<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> insert_iterator<span class="sy1">&lt;</span>Container<span class="sy1">&gt;</span>
      inserter<span class="br0">(</span>Container<span class="sy3">&amp;</span> x, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/iterator_t"><span class="kw2893">ranges::<span class="me2">iterator_t</span></span></a><span class="sy1">&lt;</span>Container<span class="sy1">&gt;</span> i<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="co1">// move iterators and sentinels</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It<span class="sy1">&gt;</span> <span class="kw1">class</span> move_iterator<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&lt;=</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">&gt;=</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, three_way_comparable_with<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> compare_three_way_result_t<span class="sy1">&lt;</span>It1, It2<span class="sy1">&gt;</span>
      operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It1, <span class="kw1">class</span> It2<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It1<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
      <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>x.<span class="me1">base</span><span class="br0">(</span><span class="br0">)</span> <span class="sy2">-</span> y.<span class="me1">base</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> move_iterator<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span>
      operator<span class="sy2">+</span><span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span> n, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> It<span class="sy1">&gt;</span>
    <span class="kw4">constexpr</span> move_iterator<span class="sy1">&lt;</span>It<span class="sy1">&gt;</span> make_move_iterator<span class="br0">(</span>It i<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>semiregular S<span class="sy1">&gt;</span> <span class="kw1">class</span> move_sentinel<span class="sy4">;</span>
 
  <span class="co1">// common iterators</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
    requires <span class="br0">(</span><span class="sy3">!</span>same_as<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="br0">)</span>
      <span class="kw1">class</span> common_iterator<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S<span class="sy1">&gt;</span>
    <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span>common_iterator<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_iterator I, <span class="kw1">class</span> S<span class="sy1">&gt;</span>
    <span class="kw1">struct</span> iterator_traits<span class="sy1">&lt;</span>common_iterator<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="co1">// default sentinel</span>
  <span class="kw1">struct</span> default_sentinel_t<span class="sy4">;</span>
  <span class="kw1">inline</span> <span class="kw4">constexpr</span> default_sentinel_t default_sentinel<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
 
  <span class="co1">// counted iterators</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I<span class="sy1">&gt;</span> <span class="kw1">class</span> counted_iterator<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_iterator I<span class="sy1">&gt;</span>
    requires <span class="coMULTI">/* see description */</span>
    <span class="kw1">struct</span> iterator_traits<span class="sy1">&lt;</span>counted_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
 
  <span class="co1">// unreachable sentinel</span>
  <span class="kw1">struct</span> unreachable_sentinel_t<span class="sy4">;</span>
  <span class="kw1">inline</span> <span class="kw4">constexpr</span> unreachable_sentinel_t unreachable_sentinel<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
 
  <span class="co1">// stream iterators</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> CharT <span class="sy1">=</span> <span class="kw4">char</span>, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;</span>,
           <span class="kw1">class</span> Distance <span class="sy1">=</span> ptrdiff_t<span class="sy1">&gt;</span>
  <span class="kw1">class</span> istream_iterator<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits, <span class="kw1">class</span> Distance<span class="sy1">&gt;</span>
    <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> istream_iterator<span class="sy1">&lt;</span>T, CharT, Traits, Distance<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x,
                    <span class="kw4">const</span> istream_iterator<span class="sy1">&lt;</span>T, CharT, Traits, Distance<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> CharT <span class="sy1">=</span> <span class="kw4">char</span>, <span class="kw1">class</span> traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
      <span class="kw1">class</span> ostream_iterator<span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
    <span class="kw1">class</span> istreambuf_iterator<span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits<span class="sy1">&gt;</span>
    <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> istreambuf_iterator<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy3">&amp;</span> a,
                    <span class="kw4">const</span> istreambuf_iterator<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy3">&amp;</span> b<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
    <span class="kw1">class</span> ostreambuf_iterator<span class="sy4">;</span>
 
  <span class="co1">// range access</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span>C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> begin<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span>C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> end<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> T<span class="sy2">*</span> begin<span class="br0">(</span>T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> T<span class="sy2">*</span> end<span class="br0">(</span>T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> cbegin<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/begin.html"><span class="kw678">std::<span class="me2">begin</span></span></a><span class="br0">(</span>c<span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
    <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span><a href="../iterator/begin.html"><span class="kw678">std::<span class="me2">begin</span></span></a><span class="br0">(</span>c<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> cend<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/end.html"><span class="kw682">std::<span class="me2">end</span></span></a><span class="br0">(</span>c<span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
    <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span><a href="../iterator/end.html"><span class="kw682">std::<span class="me2">end</span></span></a><span class="br0">(</span>c<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> rbegin<span class="br0">(</span>C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">rbegin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> rbegin<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">rbegin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> rend<span class="br0">(</span>C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">rend</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> rend<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">rend</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span>T<span class="sy2">*</span><span class="sy1">&gt;</span> rbegin<span class="br0">(</span>T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span>T<span class="sy2">*</span><span class="sy1">&gt;</span> rend<span class="br0">(</span>T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> E<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span><span class="kw4">const</span> E<span class="sy2">*</span><span class="sy1">&gt;</span> rbegin<span class="br0">(</span>initializer_list<span class="sy1">&lt;</span>E<span class="sy1">&gt;</span> il<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> E<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> reverse_iterator<span class="sy1">&lt;</span><span class="kw4">const</span> E<span class="sy2">*</span><span class="sy1">&gt;</span> rend<span class="br0">(</span>initializer_list<span class="sy1">&lt;</span>E<span class="sy1">&gt;</span> il<span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> crbegin<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span><a href="../iterator/rbegin.html"><span class="kw680">std::<span class="me2">rbegin</span></span></a><span class="br0">(</span>c<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> crend<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span><a href="../iterator/rend.html"><span class="kw684">std::<span class="me2">rend</span></span></a><span class="br0">(</span>c<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> size<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> size_t size<span class="br0">(</span><span class="kw4">const</span> T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> ssize<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span>
    <span class="sy2">-</span><span class="sy1">&gt;</span> common_type_t<span class="sy1">&lt;</span>ptrdiff_t, make_signed_t<span class="sy1">&lt;</span>decltype<span class="br0">(</span>c.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, ptrdiff_t N<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> ptrdiff_t ssize<span class="br0">(</span><span class="kw4">const</span> T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="br0">[</span><span class="br0">[</span>nodiscard<span class="br0">]</span><span class="br0">]</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> empty<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">empty</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span> <span class="br0">[</span><span class="br0">[</span>nodiscard<span class="br0">]</span><span class="br0">]</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span><span class="kw4">const</span> T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> E<span class="sy1">&gt;</span> <span class="br0">[</span><span class="br0">[</span>nodiscard<span class="br0">]</span><span class="br0">]</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> empty<span class="br0">(</span>initializer_list<span class="sy1">&lt;</span>E<span class="sy1">&gt;</span> il<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> data<span class="br0">(</span>C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">data</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> C<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">auto</span> data<span class="br0">(</span><span class="kw4">const</span> C<span class="sy3">&amp;</span> c<span class="br0">)</span> <span class="sy2">-</span><span class="sy1">&gt;</span> decltype<span class="br0">(</span>c.<span class="me1">data</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, size_t N<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> T<span class="sy2">*</span> data<span class="br0">(</span>T <span class="br0">(</span><span class="sy3">&amp;</span>a<span class="br0">)</span><span class="br0">[</span>N<span class="br0">]</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> E<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">const</span> E<span class="sy2">*</span> data<span class="br0">(</span>initializer_list<span class="sy1">&lt;</span>E<span class="sy1">&gt;</span> il<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_readable">Concept <a href="../iterator/indirectly_readable.html" title="cpp/iterator/indirectly readable"><code>indirectly_readable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In<span class="sy1">&gt;</span>
    concept __indirectlyReadableImpl <span class="sy1">=</span> <span class="co1">// exposition only</span>
      requires<span class="br0">(</span><span class="kw4">const</span> In in<span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">typename</span> iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="kw1">typename</span> iter_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="kw1">typename</span> iter_rvalue_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> <span class="sy2">*</span>in <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span>
        <span class="br0">{</span> iter_move<span class="br0">(</span>in<span class="br0">)</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>iter_rvalue_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span>
      <span class="br0">}</span> <span class="sy3">&amp;&amp;</span>
      common_reference_with<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span>, iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      common_reference_with<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span>, iter_rvalue_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      common_reference_with<span class="sy1">&lt;</span>iter_rvalue_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span>, <span class="kw4">const</span> iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In<span class="sy1">&gt;</span>
    concept indirectly_readable <span class="sy1">=</span>
      __indirectlyReadableImpl<span class="sy1">&lt;</span>remove_cvref_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_writable">Concept <a href="../iterator/indirectly_writable.html" title="cpp/iterator/indirectly writable"><code>indirectly_writable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Out, <span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept indirectly_writable <span class="sy1">=</span>
      requires<span class="br0">(</span>Out<span class="sy3">&amp;&amp;</span> o, T<span class="sy3">&amp;&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
        <span class="sy2">*</span>o <span class="sy1">=</span> <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// not required to be equality-preserving</span>
        <span class="sy2">*</span><a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>Out<span class="sy1">&gt;</span><span class="br0">(</span>o<span class="br0">)</span> <span class="sy1">=</span> <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span>
        <span class="co1">// not required to be equality-preserving</span>
        <span class="kw1">const_cast</span><span class="sy1">&lt;</span><span class="kw4">const</span> iter_reference_t<span class="sy1">&lt;</span>Out<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span>o<span class="br0">)</span> <span class="sy1">=</span>
        <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// not required to be equality-preserving</span>
        <span class="kw1">const_cast</span><span class="sy1">&lt;</span><span class="kw4">const</span> iter_reference_t<span class="sy1">&lt;</span>Out<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="sy2">*</span><a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>Out<span class="sy1">&gt;</span><span class="br0">(</span>o<span class="br0">)</span><span class="br0">)</span> <span class="sy1">=</span>
        <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// not required to be equality-preserving</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_weakly_incrementable">Concept <a href="../iterator/weakly_incrementable.html" title="cpp/iterator/weakly incrementable"><code>weakly_incrementable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> __is_integer_like <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span> <span class="co1">// exposition only</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">inline</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> __is_signed_integer_like <span class="sy1">=</span>  <span class="co1">// exposition only</span>
      <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept weakly_incrementable <span class="sy1">=</span>
      default_initializable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> movable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span>I i<span class="br0">)</span> <span class="br0">{</span>
        <span class="kw1">typename</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
        requires __is_signed_integer_like<span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> <span class="sy2">++</span>i <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>   <span class="co1">// not required to be equality-preserving</span>
        i<span class="sy2">++</span><span class="sy4">;</span>                      <span class="co1">// not required to be equality-preserving</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_incrementable">Concept <a href="../iterator/incrementable.html" title="cpp/iterator/incrementable"><code>incrementable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept incrementable <span class="sy1">=</span>
      regular<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      weakly_incrementable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span>I i<span class="br0">)</span> <span class="br0">{</span>
        <span class="br0">{</span> i<span class="sy2">++</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_input_or_output_iterator">Concept <a href="../iterator/input_or_output_iterator.html" title="cpp/iterator/input or output iterator"><code>input_or_output_iterator</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept input_or_output_iterator <span class="sy1">=</span>
      requires<span class="br0">(</span>I i<span class="br0">)</span> <span class="br0">{</span>
        <span class="br0">{</span> <span class="sy2">*</span>i <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> can<span class="sy2">-</span>reference<span class="sy4">;</span>
      <span class="br0">}</span> <span class="sy3">&amp;&amp;</span>
      weakly_incrementable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_sentinel_for">Concept <a href="../iterator/sentinel_for.html" title="cpp/iterator/sentinel for"><code>sentinel_for</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> S, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept sentinel_for <span class="sy1">=</span>
      semiregular<span class="sy1">&lt;</span>S<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      input_or_output_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      __WeaklyEqualityComparableWith<span class="sy1">&lt;</span>S, I<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_sized_sentinel_for">Concept <a href="../iterator/sized_sentinel_for.html" title="cpp/iterator/sized sentinel for"><code>sized_sentinel_for</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> S, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept sized_sentinel_for <span class="sy1">=</span>
      sentinel_for<span class="sy1">&lt;</span>S, I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      <span class="sy3">!</span>disable_sized_sentinel<span class="sy1">&lt;</span>remove_cv_t<span class="sy1">&lt;</span>S<span class="sy1">&gt;</span>, remove_cv_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span><span class="kw4">const</span> I<span class="sy3">&amp;</span> i, <span class="kw4">const</span> S<span class="sy3">&amp;</span> s<span class="br0">)</span> <span class="br0">{</span>
        <span class="br0">{</span> s <span class="sy2">-</span> i <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> i <span class="sy2">-</span> s <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_input_iterator">Concept <a href="../iterator/input_iterator.html" title="cpp/iterator/input iterator"><code>input_iterator</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept input_iterator <span class="sy1">=</span>
      input_or_output_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_readable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires <span class="br0">{</span> <span class="kw1">typename</span> <span class="coMULTI">/*ITER_CONCEPT*/</span><span class="br0">(</span>I<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span> <span class="sy3">&amp;&amp;</span>
      derived_from<span class="sy1">&lt;</span><span class="coMULTI">/*ITER_CONCEPT*/</span><span class="br0">(</span>I<span class="br0">)</span>, input_iterator_tag<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_output_iterator">Concept <a href="../iterator/output_iterator.html" title="cpp/iterator/output iterator"><code>output_iterator</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> T<span class="sy1">&gt;</span>
    concept output_iterator <span class="sy1">=</span>
      input_or_output_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>I, T<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span>I i, T<span class="sy3">&amp;&amp;</span> t<span class="br0">)</span> <span class="br0">{</span>
        <span class="sy2">*</span>i<span class="sy2">++</span> <span class="sy1">=</span> <a href="../utility/forward.html"><span class="kw1120">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="br0">(</span>t<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// not required to be equality-preserving</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_forward_iterator">Concept <a href="../iterator/forward_iterator.html" title="cpp/iterator/forward iterator"><code>forward_iterator</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept forward_iterator <span class="sy1">=</span>
      input_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      derived_from<span class="sy1">&lt;</span><span class="coMULTI">/*ITER_CONCEPT*/</span><span class="br0">(</span>I<span class="br0">)</span>, forward_iterator_tag<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      incrementable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      sentinel_for<span class="sy1">&lt;</span>I, I<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_bidirectional_iterator">Concept <a href="../iterator/bidirectional_iterator.html" title="cpp/iterator/bidirectional iterator"><code>bidirectional_iterator</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept bidirectional_iterator <span class="sy1">=</span>
      forward_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      derived_from<span class="sy1">&lt;</span><span class="coMULTI">/*ITER_CONCEPT*/</span><span class="br0">(</span>I<span class="br0">)</span>, bidirectional_iterator_tag<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span>I i<span class="br0">)</span> <span class="br0">{</span>
        <span class="br0">{</span> <span class="sy2">--</span>i <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> i<span class="sy2">--</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_random_access_iterator">Concept <a href="../iterator/random_access_iterator.html" title="cpp/iterator/random access iterator"><code>random_access_iterator</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept random_access_iterator <span class="sy1">=</span>
      bidirectional_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      derived_from<span class="sy1">&lt;</span><span class="coMULTI">/*ITER_CONCEPT*/</span><span class="br0">(</span>I<span class="br0">)</span>, random_access_iterator_tag<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      totally_ordered<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      sized_sentinel_for<span class="sy1">&lt;</span>I, I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span>I i, <span class="kw4">const</span> I j, <span class="kw4">const</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="br0">{</span>
        <span class="br0">{</span> i <span class="sy2">+</span><span class="sy1">=</span> n <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> j <span class="sy2">+</span>  n <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> n <span class="sy2">+</span>  j <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> i <span class="sy2">-</span><span class="sy1">=</span> n <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span> j <span class="sy2">-</span>  n <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
        <span class="br0">{</span>  j<span class="br0">[</span>n<span class="br0">]</span>  <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_contiguous_iterator">Concept <a href="../iterator/contiguous_iterator.html" title="cpp/iterator/contiguous iterator"><code>contiguous_iterator</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept contiguous_iterator <span class="sy1">=</span>
      random_access_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      derived_from<span class="sy1">&lt;</span><span class="coMULTI">/*ITER_CONCEPT*/</span><span class="br0">(</span>I<span class="br0">)</span>, contiguous_iterator_tag<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      is_lvalue_reference_v<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      same_as<span class="sy1">&lt;</span>iter_value_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span>, remove_cvref_t<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span><span class="kw4">const</span> I<span class="sy3">&amp;</span> i<span class="br0">)</span> <span class="br0">{</span>
        <span class="br0">{</span> to_address<span class="br0">(</span>i<span class="br0">)</span> <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> same_as<span class="sy1">&lt;</span>add_pointer_t<span class="sy1">&lt;</span>iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_unary_invocable">Concept <a href="../iterator/indirectly_unary_invocable.html" title="cpp/iterator/indirectly unary invocable"><code>indirectly_unary_invocable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept indirectly_unary_invocable <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      copy_constructible<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      common_reference_with<span class="sy1">&lt;</span>
        invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span>,
        invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_regular_unary_invocable">Concept <a href="../iterator/indirectly_unary_invocable.html" title="cpp/iterator/indirectly unary invocable"><code>indirectly_regular_unary_invocable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept indirectly_regular_unary_invocable <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      copy_constructible<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      regular_invocable<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      common_reference_with<span class="sy1">&lt;</span>
        invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span>,
        invoke_result_t<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirect_unary_predicate">Concept <a href="../iterator/indirect_unary_predicate.html" title="cpp/iterator/indirect unary predicate"><code>indirect_unary_predicate</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept indirect_unary_predicate <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      copy_constructible<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirect_binary_predicate">Concept <a href="../iterator/indirect_binary_predicate.html" title="cpp/iterator/indirect binary predicate"><code>indirect_binary_predicate</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I1, <span class="kw1">class</span> I2 <span class="sy1">=</span> I1<span class="sy1">&gt;</span>
    concept indirect_binary_predicate <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> indirectly_readable<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      copy_constructible<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_value_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      predicate<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirect_equivalence_relation">Concept <a href="../iterator/indirect_equivalence_relation.html" title="cpp/iterator/indirect equivalence relation"><code>indirect_equivalence_relation</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I1, <span class="kw1">class</span> I2 <span class="sy1">=</span> I1<span class="sy1">&gt;</span>
    concept indirect_equivalence_relation <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> indirectly_readable<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      copy_constructible<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      equivalence_relation<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      equivalence_relation<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      equivalence_relation<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_value_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      equivalence_relation<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      equivalence_relation<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirect_strict_weak_order">Concept <a href="../iterator/indirect_strict_weak_order.html" title="cpp/iterator/indirect strict weak order"><code>indirect_strict_weak_order</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> F, <span class="kw1">class</span> I1, <span class="kw1">class</span> I2 <span class="sy1">=</span> I1<span class="sy1">&gt;</span>
    concept indirect_strict_weak_order <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> indirectly_readable<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      copy_constructible<span class="sy1">&lt;</span>F<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      strict_weak_order<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      strict_weak_order<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_value_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      strict_weak_order<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_value_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      strict_weak_order<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      strict_weak_order<span class="sy1">&lt;</span>F<span class="sy3">&amp;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span>, iter_common_reference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_movable">Concept <a href="../iterator/indirectly_movable.html" title="cpp/iterator/indirectly movable"><code>indirectly_movable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_movable <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>Out, iter_rvalue_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_movable_storable">Concept <a href="../iterator/indirectly_movable_storable.html" title="cpp/iterator/indirectly movable storable"><code>indirectly_movable_storable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_movable_storable <span class="sy1">=</span>
      indirectly_movable<span class="sy1">&lt;</span>In, Out<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>Out, iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      movable<span class="sy1">&lt;</span>iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      constructible_from<span class="sy1">&lt;</span>iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span>, iter_rvalue_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      assignable_from<span class="sy1">&lt;</span>iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_rvalue_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_copyable">Concept <a href="../iterator/indirectly_copyable.html" title="cpp/iterator/indirectly copyable"><code>indirectly_copyable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_copyable <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>Out, iter_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_copyable_storable">Concept <a href="../iterator/indirectly_copyable_storable.html" title="cpp/iterator/indirectly copyable storable"><code>indirectly_copyable_storable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> In, <span class="kw1">class</span> Out<span class="sy1">&gt;</span>
    concept indirectly_copyable_storable <span class="sy1">=</span>
      indirectly_copyable<span class="sy1">&lt;</span>In, Out<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>Out, iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>Out, <span class="kw4">const</span> iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>Out, iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_writable<span class="sy1">&lt;</span>Out, <span class="kw4">const</span> iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      copyable<span class="sy1">&lt;</span>iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      constructible_from<span class="sy1">&lt;</span>iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span>, iter_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span> <span class="sy3">&amp;&amp;</span>
      assignable_from<span class="sy1">&lt;</span>iter_value_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;</span><span class="sy3">&amp;</span>, iter_reference_t<span class="sy1">&lt;</span>In<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_swappable">Concept <a href="../iterator/indirectly_swappable.html" title="cpp/iterator/indirectly swappable"><code>indirectly_swappable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I1, <span class="kw1">class</span> I2 <span class="sy1">=</span> I1<span class="sy1">&gt;</span>
    concept indirectly_swappable <span class="sy1">=</span>
      indirectly_readable<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> indirectly_readable<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      requires<span class="br0">(</span><span class="kw4">const</span> I1 i1, <span class="kw4">const</span> I2 i2<span class="br0">)</span> <span class="br0">{</span>
        <a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>i1, i1<span class="br0">)</span><span class="sy4">;</span>
        <a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>i2, i2<span class="br0">)</span><span class="sy4">;</span>
        <a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>i1, i2<span class="br0">)</span><span class="sy4">;</span>
        <a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>i2, i1<span class="br0">)</span><span class="sy4">;</span>
      <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_indirectly_comparable">Concept <a href="../iterator/indirectly_comparable.html" title="cpp/iterator/indirectly comparable"><code>indirectly_comparable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I1, <span class="kw1">class</span> I2, <span class="kw1">class</span> R, <span class="kw1">class</span> P1 <span class="sy1">=</span> identity, <span class="kw1">class</span> P2 <span class="sy1">=</span> identity<span class="sy1">&gt;</span>
    concept indirectly_comparable <span class="sy1">=</span>
      indirect_predicate<span class="sy1">&lt;</span>R, <a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy1">&lt;</span>I1, P1<span class="sy1">&gt;</span>, <a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy1">&lt;</span>I2, P2<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_permutable">Concept <a href="../iterator/permutable.html" title="cpp/iterator/permutable"><code>permutable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    concept permutable <span class="sy1">=</span>
      forward_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_movable_storable<span class="sy1">&lt;</span>I, I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_swappable<span class="sy1">&lt;</span>I, I<span class="sy1">&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_mergeable">Concept <a href="../iterator/mergeable.html" title="cpp/iterator/mergeable"><code>mergeable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I1, <span class="kw1">class</span> I2, <span class="kw1">class</span> Out, <span class="kw1">class</span> R <span class="sy1">=</span> <a href="../functional/ranges/less.html"><span class="kw2847">ranges::<span class="me2">less</span></span></a>,
           <span class="kw1">class</span> P1 <span class="sy1">=</span> identity, <span class="kw1">class</span> P2 <span class="sy1">=</span> identity<span class="sy1">&gt;</span>
    concept mergeable <span class="sy1">=</span>
      input_iterator<span class="sy1">&lt;</span>I1<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      input_iterator<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      weakly_incrementable<span class="sy1">&lt;</span>Out<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_copyable<span class="sy1">&lt;</span>I1, Out<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirectly_copyable<span class="sy1">&lt;</span>I2, Out<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirect_strict_weak_order<span class="sy1">&lt;</span>R, <a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy1">&lt;</span>I1, P1<span class="sy1">&gt;</span>, <a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy1">&lt;</span>I2, P2<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Concept_sortable">Concept <a href="../iterator/sortable.html" title="cpp/iterator/sortable"><code>sortable</code></a></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> R <span class="sy1">=</span> <a href="../functional/ranges/less.html"><span class="kw2847">ranges::<span class="me2">less</span></span></a>, <span class="kw1">class</span> P <span class="sy1">=</span> identity<span class="sy1">&gt;</span>
    concept sortable <span class="sy1">=</span>
      permutable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
      indirect_strict_weak_order<span class="sy1">&lt;</span>R, <a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy1">&lt;</span>I, P<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::incrementable_traits">Class template <span class="t-lc"><a href="../iterator/incrementable_traits.html" title="cpp/iterator/incrementable traits">std::incrementable_traits</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> incrementable_traits <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span>T<span class="sy2">*</span><span class="sy1">&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span><span class="kw4">const</span> I<span class="sy1">&gt;</span>
    <span class="sy4">:</span> incrementable_traits<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires requires <span class="br0">{</span> <span class="kw1">typename</span> T<span class="sy4">::</span><span class="me2">difference_type</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> <span class="kw1">typename</span> T<span class="sy4">::</span><span class="me2">difference_type</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires <span class="br0">(</span><span class="sy3">!</span>requires <span class="br0">{</span> <span class="kw1">typename</span> T<span class="sy4">::</span><span class="me2">difference_type</span><span class="sy4">;</span> <span class="br0">}</span> <span class="sy3">&amp;&amp;</span>
              requires<span class="br0">(</span><span class="kw4">const</span> T<span class="sy3">&amp;</span> a, <span class="kw4">const</span> T<span class="sy3">&amp;</span> b<span class="br0">)</span> <span class="br0">{</span> <span class="br0">{</span> a <span class="sy2">-</span> b <span class="br0">}</span> <span class="sy2">-</span><span class="sy1">&gt;</span> integral<span class="sy4">;</span> <span class="br0">}</span><span class="br0">)</span>
  <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> make_signed_t<span class="sy1">&lt;</span>decltype<span class="br0">(</span>declval<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="sy2">-</span> declval<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    <span class="kw1">using</span> iter_difference_t <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::indirectly_readable_traits">Class template <span class="t-lc"><a href="../iterator/indirectly_readable_traits.html" title="cpp/iterator/indirectly readable traits">std::indirectly_readable_traits</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> __cond_value_type <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>   <span class="co1">// exposition only</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> __cond_value_type <span class="br0">{</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> remove_cv_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span><span class="sy1">&gt;</span> <span class="kw1">struct</span> indirectly_readable_traits <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> indirectly_readable_traits<span class="sy1">&lt;</span>T<span class="sy2">*</span><span class="sy1">&gt;</span>
    <span class="sy4">:</span> __cond_value_type<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
    requires is_array_v<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> indirectly_readable_traits<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> remove_cv_t<span class="sy1">&lt;</span>remove_extent_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> indirectly_readable_traits<span class="sy1">&lt;</span><span class="kw4">const</span> I<span class="sy1">&gt;</span>
    <span class="sy4">:</span> indirectly_readable_traits<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires requires <span class="br0">{</span> <span class="kw1">typename</span> T<span class="sy4">::</span><span class="me2">value_type</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="kw1">struct</span> indirectly_readable_traits<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
    <span class="sy4">:</span> __cond_value_type<span class="sy1">&lt;</span><span class="kw1">typename</span> T<span class="sy4">::</span><span class="me2">value_type</span><span class="sy1">&gt;</span> <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires requires <span class="br0">{</span> <span class="kw1">typename</span> T<span class="sy4">::</span><span class="me2">element_type</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="kw1">struct</span> indirectly_readable_traits<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
    <span class="sy4">:</span> __cond_value_type<span class="sy1">&lt;</span><span class="kw1">typename</span> T<span class="sy4">::</span><span class="me2">element_type</span><span class="sy1">&gt;</span> <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::projected">Class template <span class="t-lc"><a href="../iterator/projected.html" title="cpp/iterator/projected">std::projected</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>indirectly_readable I, indirectly_regular_unary_invocable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> Proj<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> <a href="../iterator/projected.html"><span class="kw2681">projected</span></a> <span class="br0">{</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> remove_cvref_t<span class="sy1">&lt;</span>indirect_result_t<span class="sy1">&lt;</span>Proj<span class="sy3">&amp;</span>, I<span class="sy1">&gt;&gt;</span><span class="sy4">;</span>
    indirect_result_t<span class="sy1">&lt;</span>Proj<span class="sy3">&amp;</span>, I<span class="sy1">&gt;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span> <span class="co1">// not defined</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>weakly_incrementable I, <span class="kw1">class</span> Proj<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span><a href="../iterator/projected.html"><span class="kw2681">projected</span></a><span class="sy1">&lt;</span>I, Proj<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::iterator_traits">Class template <span class="t-lc"><a href="../iterator/iterator_traits.html" title="cpp/iterator/iterator traits">std::iterator_traits</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> iterator_traits <span class="br0">{</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span>
    requires is_object_v<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> iterator_traits<span class="sy1">&lt;</span>T<span class="sy2">*</span><span class="sy1">&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> contiguous_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> random_access_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> remove_cv_t<span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> T<span class="sy2">*</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> T<span class="sy3">&amp;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Iterator_tags">Iterator tags</span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">struct</span> input_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> output_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> forward_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> input_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> bidirectional_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> forward_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> random_access_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> bidirectional_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
  <span class="kw1">struct</span> contiguous_iterator_tag<span class="sy4">:</span> <span class="kw1">public</span> random_access_iterator_tag <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::reverse_iterator">Class template <span class="t-lc"><a href="../iterator/reverse_iterator.html" title="cpp/iterator/reverse iterator">std::reverse_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Iter<span class="sy1">&gt;</span>
  <span class="kw1">class</span> reverse_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_type     <span class="sy1">=</span> Iter<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> iter_value_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> iter_difference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="kw1">typename</span> iterator_traits<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">pointer</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> iter_reference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> reverse_iterator<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> reverse_iterator<span class="br0">(</span>Iter x<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> reverse_iterator<span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>U<span class="sy1">&gt;</span><span class="sy3">&amp;</span> u<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> reverse_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>U<span class="sy1">&gt;</span><span class="sy3">&amp;</span> u<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> Iter base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reference operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> pointer   operator<span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> requires <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reverse_iterator  operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reverse_iterator  operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> reverse_iterator  operator<span class="sy2">+</span> <span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reverse_iterator  operator<span class="sy2">-</span> <span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reverse_iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="coMULTI">/* unspecified */</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_rvalue_reference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span>
      iter_move<span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy3">&amp;</span> i<span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>indirectly_swappable<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span> Iter2<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span>
        iter_swap<span class="br0">(</span><span class="kw4">const</span> reverse_iterator<span class="sy3">&amp;</span> x,
                  <span class="kw4">const</span> reverse_iterator<span class="sy1">&lt;</span>Iter2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see description */</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">protected</span><span class="sy4">:</span>
    Iter current<span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::back_insert_iterator">Class template <span class="t-lc"><a href="../iterator/back_insert_iterator.html" title="cpp/iterator/back insert iterator">std::back_insert_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span>
  <span class="kw1">class</span> back_insert_iterator <span class="br0">{</span>
  <span class="kw1">protected</span><span class="sy4">:</span>
    Container<span class="sy2">*</span> container <span class="sy1">=</span> nullptr<span class="sy4">;</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> output_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> container_type    <span class="sy1">=</span> Container<span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> back_insert_iterator<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> back_insert_iterator<span class="br0">(</span>Container<span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> back_insert_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> <span class="kw1">typename</span> Container<span class="sy4">::</span><span class="me2">value_type</span><span class="sy3">&amp;</span> value<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> back_insert_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw1">typename</span> Container<span class="sy4">::</span><span class="me2">value_type</span><span class="sy3">&amp;&amp;</span> value<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> back_insert_iterator<span class="sy3">&amp;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> back_insert_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> back_insert_iterator  operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::front_insert_iterator">Class template <span class="t-lc"><a href="../iterator/front_insert_iterator.html" title="cpp/iterator/front insert iterator">std::front_insert_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span>
  <span class="kw1">class</span> front_insert_iterator <span class="br0">{</span>
  <span class="kw1">protected</span><span class="sy4">:</span>
    Container<span class="sy2">*</span> container <span class="sy1">=</span> nullptr<span class="sy4">;</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> output_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> container_type    <span class="sy1">=</span> Container<span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> front_insert_iterator<span class="br0">(</span>Container<span class="sy3">&amp;</span> x<span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> front_insert_iterator<span class="br0">(</span>Container<span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> front_insert_iterator<span class="sy3">&amp;</span>
      operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> <span class="kw1">typename</span> Container<span class="sy4">::</span><span class="me2">value_type</span><span class="sy3">&amp;</span> value<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> front_insert_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw1">typename</span> Container<span class="sy4">::</span><span class="me2">value_type</span><span class="sy3">&amp;&amp;</span> value<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> front_insert_iterator<span class="sy3">&amp;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> front_insert_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> front_insert_iterator  operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::insert_iterator">Class template <span class="t-lc"><a href="../iterator/insert_iterator.html" title="cpp/iterator/insert iterator">std::insert_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Container<span class="sy1">&gt;</span>
  <span class="kw1">class</span> insert_iterator <span class="br0">{</span>
  <span class="kw1">protected</span><span class="sy4">:</span>
    Container<span class="sy2">*</span> container <span class="sy1">=</span> nullptr<span class="sy4">;</span>
    <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/iterator_t"><span class="kw2893">ranges::<span class="me2">iterator_t</span></span></a><span class="sy1">&lt;</span>Container<span class="sy1">&gt;</span> iter <span class="sy1">=</span> <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/iterator_t"><span class="kw2893">ranges::<span class="me2">iterator_t</span></span></a><span class="sy1">&lt;</span>Container<span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> output_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> container_type    <span class="sy1">=</span> Container<span class="sy4">;</span>
 
    insert_iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> insert_iterator<span class="br0">(</span>Container<span class="sy3">&amp;</span> x, <a href="../../../http:/en.cppreference.com/w/cpp/ranges-ranges-placeholder/iterator_t"><span class="kw2893">ranges::<span class="me2">iterator_t</span></span></a><span class="sy1">&lt;</span>Container<span class="sy1">&gt;</span> i<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> insert_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> <span class="kw1">typename</span> Container<span class="sy4">::</span><span class="me2">value_type</span><span class="sy3">&amp;</span> value<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> insert_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw1">typename</span> Container<span class="sy4">::</span><span class="me2">value_type</span><span class="sy3">&amp;&amp;</span> value<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> insert_iterator<span class="sy3">&amp;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> insert_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> insert_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::move_iterator">Class template <span class="t-lc"><a href="../iterator/move_iterator.html" title="cpp/iterator/move iterator">std::move_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Iter<span class="sy1">&gt;</span>
  <span class="kw1">class</span> move_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_type     <span class="sy1">=</span> Iter<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_concept  <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> iter_value_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> iter_difference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> Iter<span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> iter_rvalue_reference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> move_iterator<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> move_iterator<span class="br0">(</span>Iter i<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> move_iterator<span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>U<span class="sy1">&gt;</span><span class="sy3">&amp;</span> u<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> move_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>U<span class="sy1">&gt;</span><span class="sy3">&amp;</span> u<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> iterator_type base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iterator_type base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reference operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> pointer operator<span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> move_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> move_iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> move_iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> move_iterator operator<span class="sy2">+</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> move_iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> move_iterator operator<span class="sy2">-</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> move_iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>difference_type n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> reference operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>difference_type n<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>sentinel_for<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span>
        operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_sentinel<span class="sy1">&lt;</span>S<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>sized_sentinel_for<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span>
        operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> move_sentinel<span class="sy1">&lt;</span>S<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>sized_sentinel_for<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span>
        operator<span class="sy2">-</span><span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_sentinel<span class="sy1">&lt;</span>S<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_rvalue_reference_t<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span>
      iter_move<span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
        <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>i.<span class="me1">current</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>indirectly_swappable<span class="sy1">&lt;</span>Iter<span class="sy1">&gt;</span> Iter2<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span>
        iter_swap<span class="br0">(</span><span class="kw4">const</span> move_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> move_iterator<span class="sy1">&lt;</span>Iter2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
          <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>x.<span class="me1">current</span>, y.<span class="me1">current</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    Iter current<span class="sy4">;</span>     <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::move_sentinel">Class template <span class="t-lc"><a href="../iterator/move_sentinel.html" title="cpp/iterator/move sentinel">std::move_sentinel</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>semiregular S<span class="sy1">&gt;</span>
  <span class="kw1">class</span> move_sentinel <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw4">constexpr</span> move_sentinel<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw1">explicit</span> move_sentinel<span class="br0">(</span>S s<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> S2<span class="sy1">&gt;</span>
      requires convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> S2<span class="sy3">&amp;</span>, S<span class="sy1">&gt;</span>
        <span class="kw4">constexpr</span> move_sentinel<span class="br0">(</span><span class="kw4">const</span> move_sentinel<span class="sy1">&lt;</span>S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> s<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> S2<span class="sy1">&gt;</span>
      requires assignable_from<span class="sy1">&lt;</span>S<span class="sy3">&amp;</span>, <span class="kw4">const</span> S2<span class="sy3">&amp;</span><span class="sy1">&gt;</span>
        <span class="kw4">constexpr</span> move_sentinel<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> move_sentinel<span class="sy1">&lt;</span>S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> s<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> S base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
  <span class="kw1">private</span><span class="sy4">:</span>
    S last<span class="sy4">;</span>     <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::common_iterator">Class template <span class="t-lc"><a href="../iterator/common_iterator.html" title="cpp/iterator/common iterator">std::common_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S<span class="sy1">&gt;</span>
    requires <span class="br0">(</span><span class="sy3">!</span>same_as<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> copyable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="br0">)</span>
  <span class="kw1">class</span> common_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw4">constexpr</span> common_iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> common_iterator<span class="br0">(</span>I i<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> common_iterator<span class="br0">(</span>S s<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I2, <span class="kw1">class</span> S2<span class="sy1">&gt;</span>
      requires convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> I2<span class="sy3">&amp;</span>, I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> S2<span class="sy3">&amp;</span>, S<span class="sy1">&gt;</span>
        <span class="kw4">constexpr</span> common_iterator<span class="br0">(</span><span class="kw4">const</span> common_iterator<span class="sy1">&lt;</span>I2, S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I2, <span class="kw1">class</span> S2<span class="sy1">&gt;</span>
      requires convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> I2<span class="sy3">&amp;</span>, I<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> S2<span class="sy3">&amp;</span>, S<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span>
               assignable_from<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span>, <span class="kw4">const</span> I2<span class="sy3">&amp;</span><span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> assignable_from<span class="sy1">&lt;</span>S<span class="sy3">&amp;</span>, <span class="kw4">const</span> S2<span class="sy3">&amp;</span><span class="sy1">&gt;</span>
        common_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> common_iterator<span class="sy1">&lt;</span>I2, S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
    decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires dereferenceable<span class="sy1">&lt;</span><span class="kw4">const</span> I<span class="sy1">&gt;</span><span class="sy4">;</span>
    decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
 
    common_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I2, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S2<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>S, I2<span class="sy1">&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>
      <span class="kw4">const</span> common_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> common_iterator<span class="sy1">&lt;</span>I2, S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I2, sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S2<span class="sy1">&gt;</span>
      requires sentinel_for<span class="sy1">&lt;</span>S, I2<span class="sy1">&gt;</span> <span class="sy3">&amp;&amp;</span> equality_comparable_with<span class="sy1">&lt;</span>I, I2<span class="sy1">&gt;</span>
    <span class="kw1">friend</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>
      <span class="kw4">const</span> common_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> common_iterator<span class="sy1">&lt;</span>I2, S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>sized_sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> I2, sized_sentinel_for<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> S2<span class="sy1">&gt;</span>
      requires sized_sentinel_for<span class="sy1">&lt;</span>S, I2<span class="sy1">&gt;</span>
    <span class="kw1">friend</span> iter_difference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span> operator<span class="sy2">-</span><span class="br0">(</span>
      <span class="kw4">const</span> common_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> common_iterator<span class="sy1">&lt;</span>I2, S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> iter_rvalue_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> iter_move<span class="br0">(</span><span class="kw4">const</span> common_iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>declval<span class="sy1">&lt;</span><span class="kw4">const</span> I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
        requires input_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>indirectly_swappable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> I2, <span class="kw1">class</span> S2<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> common_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> common_iterator<span class="sy1">&lt;</span>I2, S2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
        <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>declval<span class="sy1">&lt;</span><span class="kw4">const</span> I<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span>, declval<span class="sy1">&lt;</span><span class="kw4">const</span> I2<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    variant<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;</span> v_<span class="sy4">;</span>   <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I, <span class="kw1">class</span> S<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> incrementable_traits<span class="sy1">&lt;</span>common_iterator<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_iterator I, <span class="kw1">class</span> S<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> iterator_traits<span class="sy1">&lt;</span>common_iterator<span class="sy1">&lt;</span>I, S<span class="sy1">&gt;&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> iterator_concept <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> value_type <span class="sy1">=</span> iter_value_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type <span class="sy1">=</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> pointer <span class="sy1">=</span> <span class="coMULTI">/* see description */</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference <span class="sy1">=</span> iter_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::default_sentinel_t">Class <span class="t-lc"><a href="../iterator/default_sentinel.html" title="cpp/iterator/default sentinel t">std::default_sentinel_t</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">struct</span> default_sentinel_t <span class="br0">{</span> <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::counted_iterator">Class template <span class="t-lc"><a href="../iterator/counted_iterator.html" title="cpp/iterator/counted iterator">std::counted_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_or_output_iterator I<span class="sy1">&gt;</span>
  <span class="kw1">class</span> counted_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_type <span class="sy1">=</span> I<span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> counted_iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> counted_iterator<span class="br0">(</span>I x, iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I2<span class="sy1">&gt;</span>
      requires convertible_to<span class="sy1">&lt;</span><span class="kw4">const</span> I2<span class="sy3">&amp;</span>, I<span class="sy1">&gt;</span>
        <span class="kw4">constexpr</span> counted_iterator<span class="br0">(</span><span class="kw4">const</span> counted_iterator<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> I2<span class="sy1">&gt;</span>
      requires assignable_from<span class="sy1">&lt;</span>I<span class="sy3">&amp;</span>, <span class="kw4">const</span> I2<span class="sy3">&amp;</span><span class="sy1">&gt;</span>
        <span class="kw4">constexpr</span> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> counted_iterator<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> I base<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy3">&amp;</span> requires copy_constructible<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> I base<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> count<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span>
      requires dereferenceable<span class="sy1">&lt;</span><span class="kw4">const</span> I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> <span class="kw4">auto</span> operator<span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span>
      requires contiguous_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> counted_iterator operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span>
      requires forward_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">--</span><span class="br0">(</span><span class="br0">)</span>
      requires bidirectional_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> counted_iterator operator<span class="sy2">--</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span>
      requires bidirectional_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> counted_iterator operator<span class="sy2">+</span><span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> counted_iterator operator<span class="sy2">+</span><span class="br0">(</span>
      iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n, <span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> x<span class="br0">)</span>
        requires random_access_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">+</span><span class="sy1">=</span><span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span>
      requires random_access_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> counted_iterator operator<span class="sy2">-</span><span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>common_with<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> I2<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span> operator<span class="sy2">-</span><span class="br0">(</span>
        <span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> counted_iterator<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> operator<span class="sy2">-</span><span class="br0">(</span>
      <span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> operator<span class="sy2">-</span><span class="br0">(</span>
      default_sentinel_t, <span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> counted_iterator<span class="sy3">&amp;</span> operator<span class="sy2">-</span><span class="sy1">=</span><span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span>
      requires random_access_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> decltype<span class="br0">(</span><span class="kw4">auto</span><span class="br0">)</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span>iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> n<span class="br0">)</span> <span class="kw4">const</span>
      requires random_access_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>common_with<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> I2<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>
        <span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> counted_iterator<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>
      <span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> x, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">template</span><span class="sy1">&lt;</span>common_with<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> I2<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> strong_ordering operator<span class="sy1">&lt;=&gt;</span><span class="br0">(</span>
        <span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> x, <span class="kw4">const</span> counted_iterator<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">constexpr</span> iter_rvalue_reference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> iter_move<span class="br0">(</span><span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> i<span class="br0">)</span>
      <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_move.html"><span class="kw3143">ranges::<span class="me2">iter_move</span></span></a><span class="br0">(</span>i.<span class="me1">current</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
        requires input_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>indirectly_swappable<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> I2<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">void</span> iter_swap<span class="br0">(</span><span class="kw4">const</span> counted_iterator<span class="sy3">&amp;</span> x,
                                      <span class="kw4">const</span> counted_iterator<span class="sy1">&lt;</span>I2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> y<span class="br0">)</span>
        <span class="kw1">noexcept</span><span class="br0">(</span><span class="kw1">noexcept</span><span class="br0">(</span><a href="../iterator/ranges/iter_swap.html"><span class="kw3278">ranges::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>x.<span class="me1">current</span>, y.<span class="me1">current</span><span class="br0">)</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    I current <span class="sy1">=</span> I<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>                    <span class="co1">// exposition only</span>
    iter_difference_t<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> length <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span>    <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span>input_iterator I<span class="sy1">&gt;</span>
  <span class="kw1">struct</span> iterator_traits<span class="sy1">&lt;</span>counted_iterator<span class="sy1">&lt;</span>I<span class="sy1">&gt;&gt;</span> <span class="sy4">:</span> iterator_traits<span class="sy1">&lt;</span>I<span class="sy1">&gt;</span> <span class="br0">{</span>
    <span class="kw1">using</span> pointer <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_std::unreachable_sentinel_t">Class <span class="t-lc"><a href="../iterator/unreachable_sentinel_t.html" title="cpp/iterator/unreachable sentinel t">std::unreachable_sentinel_t</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">struct</span> unreachable_sentinel_t <span class="br0">{</span>
    <span class="kw1">template</span><span class="sy1">&lt;</span>weakly_incrementable I<span class="sy1">&gt;</span>
      <span class="kw1">friend</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span>unreachable_sentinel_t, <span class="kw4">const</span> I<span class="sy3">&amp;</span><span class="br0">)</span> <span class="kw1">noexcept</span>
      <span class="br0">{</span> <span class="kw1">return</span> <span class="kw2">false</span><span class="sy4">;</span> <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::istream_iterator">Class template <span class="t-lc"><a href="../iterator/istream_iterator.html" title="cpp/iterator/istream iterator">std::istream_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> CharT <span class="sy1">=</span> <span class="kw4">char</span>, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;</span>,
           <span class="kw1">class</span> Distance <span class="sy1">=</span> ptrdiff_t<span class="sy1">&gt;</span>
  <span class="kw1">class</span> istream_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> T<span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> Distance<span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="kw4">const</span> T<span class="sy2">*</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> <span class="kw4">const</span> T<span class="sy3">&amp;</span><span class="sy4">;</span>
    <span class="kw1">using</span> char_type         <span class="sy1">=</span> CharT<span class="sy4">;</span>
    <span class="kw1">using</span> traits_type       <span class="sy1">=</span> Traits<span class="sy4">;</span>
    <span class="kw1">using</span> istream_type      <span class="sy1">=</span> basic_istream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> istream_iterator<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> istream_iterator<span class="br0">(</span>default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
    istream_iterator<span class="br0">(</span>istream_type<span class="sy3">&amp;</span> s<span class="br0">)</span><span class="sy4">;</span>
    istream_iterator<span class="br0">(</span><span class="kw4">const</span> istream_iterator<span class="sy3">&amp;</span> x<span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    ~istream_iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    istream_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> istream_iterator<span class="sy3">&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
 
    <span class="kw4">const</span> T<span class="sy3">&amp;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    <span class="kw4">const</span> T<span class="sy2">*</span> operator<span class="sy2">-</span><span class="sy1">&gt;</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    istream_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    istream_iterator  operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> istream_iterator<span class="sy3">&amp;</span> i, default_sentinel_t<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    basic_istream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy2">*</span> in_stream<span class="sy4">;</span> <span class="co1">// exposition only</span>
    T value<span class="sy4">;</span>                                 <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ostream_iterator">Class template <span class="t-lc"><a href="../iterator/ostream_iterator.html" title="cpp/iterator/ostream iterator">std::ostream_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> CharT <span class="sy1">=</span> <span class="kw4">char</span>, classTraits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> ostream_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> output_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> char_type         <span class="sy1">=</span> CharT<span class="sy4">;</span>
    <span class="kw1">using</span> traits_type       <span class="sy1">=</span> Traits<span class="sy4">;</span>
    <span class="kw1">using</span> ostream_type      <span class="sy1">=</span> basic_ostream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> ostreambuf_iterator<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    ostream_iterator<span class="br0">(</span>ostream_type<span class="sy3">&amp;</span> s<span class="br0">)</span><span class="sy4">;</span>
    ostream_iterator<span class="br0">(</span>ostream_type<span class="sy3">&amp;</span> s, <span class="kw4">const</span> CharT<span class="sy2">*</span> delimiter<span class="br0">)</span><span class="sy4">;</span>
    ostream_iterator<span class="br0">(</span><span class="kw4">const</span> ostream_iterator<span class="sy3">&amp;</span> x<span class="br0">)</span><span class="sy4">;</span>
    ~ostream_iterator<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    ostream_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> ostream_iterator<span class="sy3">&amp;</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    ostream_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> T<span class="sy3">&amp;</span> value<span class="br0">)</span><span class="sy4">;</span>
 
    ostream_iterator<span class="sy3">&amp;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    ostream_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    ostream_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    basic_ostream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy2">*</span> out_stream <span class="sy1">=</span> nullptr<span class="sy4">;</span>          <span class="co1">// exposition only</span>
    <span class="kw4">const</span> CharT<span class="sy2">*</span> delim <span class="sy1">=</span> nullptr<span class="sy4">;</span>                                <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::istreambuf_iterator">Class template <span class="t-lc"><a href="../iterator/istreambuf_iterator.html" title="cpp/iterator/istreambuf iterator">std::istreambuf_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> istreambuf_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> input_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> CharT<span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> <span class="kw1">typename</span> Traits<span class="sy4">::</span><span class="me2">off_type</span><span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="coMULTI">/* unspecified */</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> CharT<span class="sy4">;</span>
    <span class="kw1">using</span> char_type         <span class="sy1">=</span> CharT<span class="sy4">;</span>
    <span class="kw1">using</span> traits_type       <span class="sy1">=</span> Traits<span class="sy4">;</span>
    <span class="kw1">using</span> int_type          <span class="sy1">=</span> <span class="kw1">typename</span> Traits<span class="sy4">::</span><span class="me2">int_type</span><span class="sy4">;</span>
    <span class="kw1">using</span> streambuf_type    <span class="sy1">=</span> basic_streambuf<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> istream_type      <span class="sy1">=</span> basic_istream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw1">class</span> proxy<span class="sy4">;</span>                          <span class="co1">// exposition only</span>
 
    <span class="kw4">constexpr</span> istreambuf_iterator<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    <span class="kw4">constexpr</span> istreambuf_iterator<span class="br0">(</span>default_sentinel_t<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    istreambuf_iterator<span class="br0">(</span><span class="kw4">const</span> istreambuf_iterator<span class="sy3">&amp;</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    ~istreambuf_iterator<span class="br0">(</span><span class="br0">)</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    istreambuf_iterator<span class="br0">(</span>istream_type<span class="sy3">&amp;</span> s<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    istreambuf_iterator<span class="br0">(</span>streambuf_type<span class="sy2">*</span> s<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    istreambuf_iterator<span class="br0">(</span><span class="kw4">const</span> proxy<span class="sy3">&amp;</span> p<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    istreambuf_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span><span class="kw4">const</span> istreambuf_iterator<span class="sy3">&amp;</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    CharT operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
    istreambuf_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    proxy operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">bool</span> equal<span class="br0">(</span><span class="kw4">const</span> istreambuf_iterator<span class="sy3">&amp;</span> b<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span>
 
    <span class="kw1">friend</span> <span class="kw4">bool</span> operator<span class="sy1">==</span><span class="br0">(</span><span class="kw4">const</span> istreambuf_iterator<span class="sy3">&amp;</span> i, default_sentinel_t s<span class="br0">)</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    streambuf_type<span class="sy2">*</span> sbuf_<span class="sy4">;</span>                <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
 
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits<span class="sy1">&gt;</span>
  <span class="kw1">class</span> istreambuf_iterator<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">proxy</span> <span class="br0">{</span> <span class="co1">// exposition only</span>
    CharT keep_<span class="sy4">;</span>
    basic_streambuf<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy2">*</span> sbuf_<span class="sy4">;</span>
    proxy<span class="br0">(</span>CharT c, basic_streambuf<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy2">*</span> sbuf<span class="br0">)</span>
      <span class="sy4">:</span> keep_<span class="br0">(</span>c<span class="br0">)</span>, sbuf_<span class="br0">(</span>sbuf<span class="br0">)</span> <span class="br0">{</span> <span class="br0">}</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    CharT operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> keep_<span class="sy4">;</span> <span class="br0">}</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::ostreambuf_iterator">Class template <span class="t-lc"><a href="../iterator/ostreambuf_iterator.html" title="cpp/iterator/ostreambuf iterator">std::ostreambuf_iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> CharT, <span class="kw1">class</span> Traits <span class="sy1">=</span> char_traits<span class="sy1">&lt;</span>CharT<span class="sy1">&gt;&gt;</span>
  <span class="kw1">class</span> ostreambuf_iterator <span class="br0">{</span>
  <span class="kw1">public</span><span class="sy4">:</span>
    <span class="kw1">using</span> iterator_category <span class="sy1">=</span> output_iterator_tag<span class="sy4">;</span>
    <span class="kw1">using</span> value_type        <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> difference_type   <span class="sy1">=</span> ptrdiff_t<span class="sy4">;</span>
    <span class="kw1">using</span> pointer           <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> reference         <span class="sy1">=</span> <span class="kw4">void</span><span class="sy4">;</span>
    <span class="kw1">using</span> char_type         <span class="sy1">=</span> CharT<span class="sy4">;</span>
    <span class="kw1">using</span> traits_type       <span class="sy1">=</span> Traits<span class="sy4">;</span>
    <span class="kw1">using</span> streambuf_type    <span class="sy1">=</span> basic_streambuf<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy4">;</span>
    <span class="kw1">using</span> ostream_type      <span class="sy1">=</span> basic_ostream<span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span><span class="sy4">;</span>
 
    <span class="kw4">constexpr</span> ostreambuf_iterator<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
    ostreambuf_iterator<span class="br0">(</span>ostream_type<span class="sy3">&amp;</span> s<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    ostreambuf_iterator<span class="br0">(</span>streambuf_type<span class="sy2">*</span> s<span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
    ostreambuf_iterator<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>CharT c<span class="br0">)</span><span class="sy4">;</span>
 
    ostreambuf_iterator<span class="sy3">&amp;</span> operator<span class="sy2">*</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    ostreambuf_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    ostreambuf_iterator<span class="sy3">&amp;</span> operator<span class="sy2">++</span><span class="br0">(</span><span class="kw4">int</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw4">bool</span> failed<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span>
 
  <span class="kw1">private</span><span class="sy4">:</span>
    streambuf_type<span class="sy2">*</span> sbuf_ <span class="sy1">=</span> nullptr<span class="sy4">;</span>    <span class="co1">// exposition only</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<h4><span class="mw-headline" id="Class_template_std::iterator">Class template <span class="t-lc"><a href="../iterator/iterator.html" title="cpp/iterator/iterator">std::iterator</a></span></span></h4>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">namespace</span> std <span class="br0">{</span>
  <span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> Category, <span class="kw1">class</span> T, <span class="kw1">class</span> Distance <span class="sy1">=</span> ptrdiff_t,
           <span class="kw1">class</span> Pointer <span class="sy1">=</span> T<span class="sy2">*</span>, <span class="kw1">class</span> Reference <span class="sy1">=</span> T<span class="sy3">&amp;</span><span class="sy1">&gt;</span>
  <span class="kw1">struct</span> iterator <span class="br0">{</span>
    <span class="kw1">typedef</span> Category  iterator_category<span class="sy4">;</span>
    <span class="kw1">typedef</span> T         value_type<span class="sy4">;</span>
    <span class="kw1">typedef</span> Distance  difference_type<span class="sy4">;</span>
    <span class="kw1">typedef</span> Pointer   pointer<span class="sy4">;</span>
    <span class="kw1">typedef</span> Reference reference<span class="sy4">;</span>
  <span class="br0">}</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>

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